Description: ASROC (Anti-Submarine Rocket) combines a solid propellant rocket with a torpedo payload to achieve a quick reaction, all weather, intermediate range anti-submarine weapon. ASROC was designed to be installed on US Navy's surface ships inside eight-cell sealed canisters which also performed as launch ramp. Originally the US Navy deployed ASROC carrying torpedoes armed with both conventional and nuclear warheads. After launch the ASROC rocket directs to the submarine area to deliver the torpedo payload. After entry the water the torpedo powers up and searches for the submarine using either active or passive sonar.

The RUM-139 Verical Launch ASROC (VLA) was designed to be fired from vertical launch system (VLS) such as the Mk-41. VLS offers greater weapons availability and quicker response than ramps that need to be directed to the target area before launch. The VLA program was launched in 1980 with Loral as the lead contractor. The RUM-139A weapon system achieved initial operational capability (IOC) in 1993 and RUM-139B in 1996. RUM-139B is an improved variant featuring Mark 46 Mod 5A(SW) in lieu of Mark 46 Mod 5(S). Mark 46 Mod 5A(SW) is more capable than its predecessor in the shallow water environment.

The US Navy's has deployed VLAs onboard Ticonderoga-class cruisers, and Spruance- and Buke-class destroyers. The Japanese Navy also deployed VLAs on its destroyers and frigates. As of 2005, VLA deployed within the US Navy are carrying one Mark 46 Mod 5(S/SW) torpedo. RUM-139B upgrade is being retrofitted into the entire VLA stockpile. Lockheed Martin Naval Electronics & Surveillance Systems is the contractor for the VLA program replacing Loral.